Breathing gas delivery system

ABSTRACT

A breathing gas delivery system comprising a gas flow controller, at least one breathing apparatus, and at least one first length of tubing coupling the breathing apparatus to the gas flow controller. The gas flow controller has a body having an on/off switch, at least one gas input, at least one gas output, and at least one control mechanism for controlling flow of gas to the gas output. The breathing apparatus comprises a T-shaped gas input, a breathing bag coupled to the T-shaped gas input, a second length of tubing having two opposed ends, wherein one end is coupled to the other arm of the T-shaped gas input, a filter coupled the second length of tubing, and a nasal assembly coupled to the filter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/290,712, filed Mar. 1, 2019, titled “Breathing Gas Delivery System,”which claims priority to U.S. Patent Application No. 62/637,665, filedMar. 2, 2018, titled “Breathing Gas Delivery System.” The contents ofboth applications are incorporated herein by reference in theirentirety.

BACKGROUND

Mercury is the most toxic, non-radioactive element on the planet.Elemental mercury is a component of “silver amalgam” teeth fillings.When these fillings are removed from teeth, large amounts of poisonousmercury vapor are released that can negatively affect the patient,doctor, staff and the environment

Accordingly, there is a need for a breathing gas delivery system forsimultaneous use by a doctor, an assistant, and a patient during removalof mercury fillings.

SUMMARY

In a first embodiment, the present invention is directed to a breathinggas delivery system comprising a gas flow controller, three breathingapparatuses, and three first lengths of tubing coupling the breathingapparatuses to the gas flow controller.

The gas flow controller comprises a body having an on/off switch coupledto the body for controlling breathing gas flow into the flow controller,a body passageway disposed through the body, at least one gas inputdisposed within the body, the gas input comprising a gas inputpassageway disposed there through, the gas input passageway being influid communication with the body passageway, three gas outputs disposedwithin the body, each gas output comprising a gas output passagewaydisposed there through, each gas output passageway being in fluidcommunication with the body passageway and the gas input passageway, andthree control mechanisms disposed along the body, where each controlmechanism corresponds to and controls one of the three gas outputs.

Each breathing apparatus comprises a T-shaped gas input having two armscoupled to and extending perpendicularly to a body, the body having afree end, a breathing bag coupled to the free end of the body of theT-shaped gas input, a second length of tubing having two opposed ends,wherein one end is coupled to the other arm of the T-shaped gas input, afilter containing at least one layer of material coupled to the otherend of the second length of tubing, and a nasal assembly coupled to thefilter.

In a second embodiment, the present invention is directed to a breathinggas delivery system comprising a gas flow controller and at least onebreathing apparatus.

In a third embodiment, the present invention is directed to a kit forassembling a breathing gas delivery system.

Each first length of tubing has two opposed ends, wherein one end iscoupled to a breathing apparatus and the other end is coupled a gasoutput.

The gas input passageway can have a longitudinal axis that is parallelto the longitudinal axis of the body.

Each of the gas outputs can have a longitudinal axis that isperpendicular to the longitudinal axis of the body.

The control mechanisms each comprise a dial coupled to a needle valvethat extends into the body passageway and controls flow of gas to thecorresponding gas output.

Optionally, each nasal assembly comprises a nasal hood. Optionally, eachnasal assembly comprises a nasal hood and an airtight elbow coupling forcoupling the nasal hood to the filter.

Optionally, nasal hood comprises a one-way vent disposed in a side wallof the nasal hood.

In a fourth embodiment, the present invention is directed to a method ofusing the system, the method comprising the steps of: a) coupling thegas input to a gas source; b) securing a breathing apparatus to a faceof each user; and c) turning on and distributing the gas flow to each ofthe breathing apparatuses.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 is a top plan view of a breathing gas delivery system havingfeatures of the present invention;

FIG. 2 is a top plan view of a first length of tubing and a breathingapparatus of FIG. 1;

FIG. 3 is a perspective view of a flow controller according to FIG. 1;

FIG. 4 is a side plan view of the flow controller of FIG. 3;

FIG. 5 is a sectional view of the flow controller of FIG. 3, taken alongline 5-5;

FIG. 6 is a perspective view of a flow controller having only one gasoutput;

FIG. 7 is sectional view of the flow controller of FIG. 6, taken alongline 7-7;

FIG. 8 is a side plan view of a nasal hood according to FIG. 1; and

FIG. 9 is a perspective view of the nasal hood of FIG. 8, wherein aninside surface of the nasal hood is shown.

DESCRIPTION

As used herein, the following terms and variations thereof have themeanings given below, unless a different meaning is clearly intended bythe contest in which such term is used.

The terms “a,” “an,” and “the” and similar referents used herein are tobe construed to cover both the singular and the plural unless theirusage in context indicates otherwise.

As used in this disclosure, the term “comprise” and variations of theterm, such as “comprising” and “comprises,” are not intended to excludeother additives, components, integers ingredients or steps.

Referring now FIGS. 1 and 2, there is shown a breathing gas deliverysystem 100 for use during removal of mercury dental fillings from apatient. The system 100 comprises a gas flow controller 102, at leastone breathing apparatus 104 and at least one first length of tubing 106.

Referring now to FIGS. 3 through 7, the gas flow controller 102 has abody 302 with a longitudinal axis 402 extending along its length, anon/off switch/toggle 304, at least one gas input 306 and at least onegas output 308. The flow controller body 302 has a top surface 310, abottom surface 312, two end surfaces 314A and 314B, and two sidesurfaces 316A and 316B.

Each gas input 306 comprises a longitudinal axis 404 extending along itslength and each gas output 308 comprises a longitudinal axis 508extending along its length. Preferably, there are three gas outputs 308as shown in FIGS. 3 through 5. Typical dimensions of the body 302 arefrom about 1.0 inch to about 6 inches wide, from about 1.0 inch to about6 inches long, and from about 1.0 inch to about 2.0 inches thick. Theon/off switch/toggle 304 controls the breathing gas flow into the flowcontroller 102.

Optionally, as shown in FIGS. 6 and 7, the gas flow controller 102 canhave one gas input 306 and one gas output 308. This configurationdirects a one-way flow of breathing gas (oxygen) through the system. Itwas developed to allow singular usage by dentists who want theirhygienist to have a non-contaminate breathing source while polishingteeth surfaces that encompass mercury amalgam fillings. The ambient airduring this process has been assayed to have unsafe amounts of mercuryvapor emanating from polishing these surface areas.

As best seen in FIGS. 5 and 7, the gas input 306 can be threadedlydisposed within the end surface 314B of the flow controller body 302.Optionally, the gas input 306 is integrally formed with the body 302.The gas input 306 has a cylindrical gas input passageway 502 disposedthere through that is in fluid communication with a single flowcontroller body passageway 504 disposed longitudinally through the flowcontroller body 302. The gas flowing into the gas input 306 must passthrough the on/off switch mechanism 510 before the gas can enter thebody passageway 504.

As shown in the Figures, the body passageway 504 intersects and is influid communication with cylindrical gas output passageways 506 disposedwithin the gas outputs 308, allowing for breathing gas to pass throughthe flow controller body 302 and into each gas output 308.

The longitudinal axis 404 of the gas input passageway 502 is parallel tothe longitudinal axis 402 of the flow controller body 302 and isapproximately perpendicular to the longitudinal axis' 406 of the gasoutput passageways 506. The gas input 306 can be ¼ inch in diameter andcan comprise a threaded ¼-inch NPT adapter for coupling to a breathinggas source. The breathing gas source can either be an existing oxygensupply source such as a N2O/O2 inhalation sedation station, or an oxygencylinder. An example of an acceptable gas input adapter 306 is made byMedical Support Products, having a place of business in Lancaster, Pa.Green oxygen seal tape, made from polytetrafluoroethylene film,manufactured by Taegatech, can be applied to the threads of the adapter306 to ensure an airtight seal with the flow controller body 302. Thegreen seal tape is ideal because it is designed to accommodate higherpressures. The gas input 306 can withstand an internal a pressure of 100PSI (pounds per square inch).

As noted above, each gas output 308 comprises a passageway 506 with thelongitudinal axis 406 approximately perpendicular to the longitudinalaxis 402 of the flow controller body 302. Typically, if the body 302 hasmore than one gas output 308, the gas outputs 308 are spaced apart fromeach other from about 0.5 inches to about 2 inches, along thelongitudinal axis of the flow controller body 302 and are threadedlydisposed within the bottom surface 312 of the flow controller body 302.Optionally, the gas outputs 308 are integrally formed with the body 302,The gas output 308 can comprise an adapter, or manifold barb, threadedlydisposed within the bottom surface 312 of the flow controller body 302for coupling to the first length of tubing 106.

The first length of tubing 106 connects the gas output 308 to itsrespective breathing apparatus 104. Optionally, each gas output 308typically comprises a ¼ inch NPT with a 3/16 inch or a ⅜ inch tubeinside diameter output barb. An example of an acceptable gas output 308manifold barb is made by Pneumadyne, having a place of business inPlymouth, Minn. White oxygen seal tape, made frompolytetrafluoroethylene film, manufactured by Taegatech, can be appliedto the threads of the adapters 308 to ensure an airtight seal with theflow controller body 302.

On the top surface 310 of the body 302, opposite each gas output 308, isa control mechanism 318 for independently regulating each gas output308. As can be seen in FIGS. 3, 4, and 5, there are three controlmechanisms 318, one for each gas output 308. As can be seen in FIGS. 6and 7, there is one control mechanism 318 for controlling the one gasoutput 308. The control mechanism 318 can be a knob or dial coupled to aneedle valve 508 that extends into the body passageway 504, and can cutoff gas flow, or open gas flow, to the corresponding gas output 308. Theneedle valve 508 controls how much breathing gas is permitting to flowfrom the body passageway 504 to the gas output passageways 506.

Optionally, the flow controller body 302 can comprise a removablecoupling system for removably coupling a surface. Preferably, theremovable coupling system comprises hook and loop fasteners secured tothe flow controller body 302 and the surface by adhesive. The surfacecan be a countertop, tabletop, or any other stable surface near thefilling removal station. This allows the dentist or dental assistant toeasily position the flow controller body 302 in any location desired.

As shown in FIG. 1, the system 100 can comprise at least one firstlength of tubing 106, depending on the number of individuals in the roomthat require protection from mercury inhalation. Preferably the system100 comprises three first lengths of tubing 106, each first length oftubing 106 having two opposed ends 108A, 108B, where one end 108A iscoupled to one of the gas outputs 308 of the flow controller body 302,and the other end 108B is coupled to a gas input 202 of a breathingapparatus 104.

Typically, each first length of tubing 106 can have a length of fromabout 12 inches to about 84 inches, a diameter of from about 3/16 inchesto about ½ inch, and can be smooth bore or three-channel safety tubingmade from flexible DEHP plastic, soft PVC plastic, vinyl, non-latexrubber or natural rubber latex. If the first length of tubing 106 ismade from three-channel tubing, the three-channels help the tubing 106resist kinks and occlusions. The tubing 106 also has no “memory” so itwill remain straight when uncoiled, decreasing pull on cannulas andincreasing overall comfort for the individuals wearing the breathingapparatuses 104. An example of an acceptable first length of tubing 106is oxygen tubing sold by Salter Labs, having a place of business inCarlsbad, Calif.

As best seen in FIG. 2, the breathing apparatuses 104 each have a gasinput 202, a breathing bag 204, a filter 206, and a nasal assembly 208.The gas input 202 is T-shaped, comprising two arms 210A, 210B that arecoupled to and extend out perpendicularly from a body 212, the body 212having a free end 214 not coupled to the arms 210A, 210B. The free end214 of the body 212 is coupled to the breathing bag 204. One of the arms210A is coupled by a tubing adapter 216 to the flow controller body 102via the first length of tubing 106. The tubing adapter 216 can have aninside diameter of 21 mm and a length of 5-7 mm, tapering to one end.Optionally, the tubing adapter 216 can have a tapering length of fromabout 0.25 inches to about 2 inches. The other arm 210B is coupled to asecond length of tubing 218 that connects to the filter 206. The arms210A, 210B of the T-shaped gas input 202 (extending along the horizontalaxis) have a 22 mm outside diameter, and the body 212 of the T-shapedgas input 202 (vertical axis) has 15 mm inside diameter and 22 mmoutside diameter connection. Examples of an acceptable tubing adapter216 and T-shaped gas input 202 are made by Hudson RCI (subsidiary ofTeleflex), having a place of business in Morrisville, N.C.

The second length of tubing 218 is typically CPAP (continuous positiveair pressure) tubing, with a smooth bore inner core and a crenelatedouter surface to create a durable, flexible tube. The second length oftubing 218 is made from plastic or PVC (polyvinyl chloride), isre-usable and washable and has durable medical grade rubber endcaps thatcreate a tight, long lasting seal with less cracking over time thanolder plastic products. An example of an acceptable second length oftubing 218 is sold by MVAP Medical Supplies, Inc., having a place ofbusiness in Newbury Park, Calif. Typically, each second length of tubing218 can have a length of from about 12 inches to about 36 inches and aninterior diameter of from about 10 mm to about 25 mm. Preferably thesecond length of tubing 218 has an interior diameter of about 19 mm, andeach endcap has a diameter of 22 mm.

The breathing bag 204 can be made from a synthetic-rubber blend,neoprene, or latex. But preferably the breathing bag 204 is latex free.It can have a capacity of 0.5 to 3 liters, and can be in a barrel or3-pleat slim design. An example of an acceptable breathing bag 204 issold by Medline Industries, Inc., having a place of business inIllinois.

One or more breathing bag orientation clips 220 can be coupled to eitherthe second length of tubing 218 or the T-shaped gas input 202 of thebreathing apparatus 104 by a connector. The clips 220 allow the user tosecure the second length of tubing 218 and/or breathing bag 204 to theirclothing so that the breathing apparatus 104 is supported and does notpull downward on the user's face. An example of an acceptable clip 220is sold by UMX Fashion Supplies, having a place of business in Walnut,Calif.

The filter 206 is a heat moisture exchanger and filters bacteria andviruses. The filter 206 comprises a housing 226 containing at least onelayer of filter material 228. Preferably the filter housing 226 containsthree layers of material 228, as shown in FIG. 2. The first two layersof material 228 are made from spun polypropylene with a calcium chloridecoating, and the third layer 228 is made from an electrostaticallycharged filter media made of polypropylene and polyolefin plastic. Thethird layer 228 is hydrophobic and captures particles that measurebetween 0.3-10 microns in size. The electrostatic properties cause thethird layer of material 228 to act like a magnet, helping it to attractboth large and small particles into the filter's 206 pleated fabric. Anexample of an acceptable filter 206 is sold under the trade nameThermoFlo™ by ARC Medical, Inc., having a place of business in Tucker,Ga. The filter 206 can be located between the nasal assembly 208 and thesecond length of tubing 218, or optionally, between the second length oftubing 218 and the T-shaped gas input 202.

The nasal assembly 208 comprises a nasal hood 222 and an air-tight elbowcoupling 224 which connects the hood 222 to the filter 206.

Referring now to FIGS. 8 and 9, the nasal hood 222 is shown. The nasalhood 222 can be made from natural or synthetic rubbers, thermoplasticelastomer (TPE), silicone or other plastics with or withoutplasticizers, and is roughly triangular in shape. The nasal hood 222 canbe either rigid or flexible. The nasal hood 222 can have, but is notlimited to, the following dimensions: an overall height of about 2inches to about 4 inches, a base 902 having an approximate width ofabout 1.5 inches to about 2.5 inches (the base 902 being the portion ofthe nasal hood 222 proximate a user's lip when the nasal hood 222 isbeing worn), an apex 904 having an approximate width of about 0.5 inchesto about 1.5 inches, and a depth of approximately 1 inch to about 2inches (the depth being the distance a user's nose is able to projectinto the nasal hood). The nasal hood 222 also comprises a non-porousgasket insert that can be placed along a perimeter of the base 902 andthe apex 904. The gasket insert is replaced for each patient.

The nasal hood 222 can comprise a one-way vent 810 disposed in a sidewall of the nasal hood 222 to allow a user to exhale inhaled breathinggas. The one-way valve 810 does not allow outside air to pass throughthe vent 810 and into the nasal hood 22. Only exhaled air is able topass out the nasal hood 222 through the vent 810.

The elbow coupling 224 can comprise a sphere 800 with two cylinders802A, 802B extending from the sphere 800, creating an approximately 90degree angled coupling. Each cylinder 802A, 802B has a proximal end 804Acoupled to the sphere 800, and a free distal end 804B extending awayfrom the sphere 800. One of the cylinders has two spaced apart flangesthat extend around the perimeter of the free distal end. The two flangeshelp the elbow coupling to securely couple to the nose pillow assembly.The term “free” means “not fastened” to the sphere. The diameter of thecylinders is from about 0.5 inches to about 1.5 inches, but preferablythe diameter is 1.0 inches.

The elbow coupling 224 can either be formed from a single piece of metalor plastic, or the elbow coupling 224 can be formed by bonding orjoining the two cylinders 802A, 802B to the sphere 800. The sphere 800and two cylinders 802A, 802B are hollow and in fluid communication witheach other, such that breathing gas from the flow controller 102 canpass into the nasal hood 222 to be inhaled by the user.

Optionally, the elbow coupling 224 can comprise a single cylinder, bentat approximately a 90 degree angle. Optionally, the elbow coupling 224can comprise a cube, with two cylinders extending therefrom. Thus, theelbow coupling 224 shape is not limited to what is described above.

As best seen in FIG. 9, there is an opening 906 disposed in the nasalhood 222 that the elbow coupling 224 is coupled to, permitting the elbowcoupling 224 to dispense breathing gas into the nasal hood 222. It isimportant for the elbow coupling 224 to be of a solid, air-tightconstruction so that no ambient, mercury tainted air can leak into thebreathing system 104 and be inhaled by the users. The elbow coupling 224can be made from stainless steel or plastic, as long as the elbowcoupling 224 is air-tight.

The nasal hood 222 can comprise one or more straps 806 to secure thenasal assembly 208 to the users' face. The straps 806 can be removablycoupled to the nasal hood 222, or the straps 806 can be permanentlycoupled to the nasal hood 222.

If the straps 806 are permanently coupled, it is achieved by eitherpermanent securing means such as clamps, rivets, glue, etc. or by beingintegrally formed with the nasal hood 222.

If the straps 806 are removably coupled, the straps 806 can be removablycoupled by several means. For example, the each side of the nasal hood222 can comprise a projection and one or both ends of the straps 806 cancomprise an opening that fits over and secures to the projections on thenasal hood 222. Optionally, each of side of the nasal hood 222 cancomprise an opening through which an end of the strap 806 threads. Thethreaded end of the strap 806 then loops back on itself, securing toitself by a clip, or hook and loop fashion. Optionally, each end of thestraps 806 secure to the sides of the nasal hood 222 by clips,preferably alligator clips, that clip onto and grip the nasal hood 222.The one or more straps 806 can be adjustable, via a sliding mechanism,or buckle system, to accommodate different users head sizes. Optionally,the one or more straps 806 can be elastic, such that they automaticallymaintain the appropriate tension on the users face. Optionally, a singlestrap 806 is used that is threaded through an passageway 808 disposedalong a bottom edge of the nasal hood 222.

In the event one strap 806 is used, the strap 806 couples to one side ofthe nasal hood 222, extends up over the users cheek, around the back ofthe users head, along the users other cheek, and couples to the otherside of the nasal hood 222. In the event two straps 806 are used, oneend of each strap 806 is coupled to one side of the nasal hood 222, andother ends of the straps 806 extend over the user's cheeks and secure toeach other at the back of the users' head. The one or more straps 806can have any shape, but preferably the straps are thin rectangles,optionally with rounded ends.

The system 100 can also comprise charcoal masks that are worn over theuser's mouth(s) to help prevent any accidental inhalation of mercuryfumes through their mouths.

As shown in FIG. 1, for those dentists who employ nitrous oxide/oxygeninhalation sedation, the system 100 can optionally comprise a 3-way TPort flow valve 110 that is attached to the oxygen inlet port of anitrous oxide/oxygen inhalation sedation system flow meter, and coupledto the gas input 306 via a standard oxygen hose with female DISSconnections at each end, should the patient require inhalation sedation.Due to the potential dental office variation of distances between the3-way T Port flow valve 110 and the gas input 306 of the gas flowcontroller 102, custom oxygen hoses will need to be made for eachpurchaser exercising this option. For those dentists who do not employthe usage of nitrous oxide/oxygen inhalation sedation the valve 110 canbe coupled directly to the gas input 306 via a standard oxygen hose withfemale DISS connections at each end. As stated above, due to thepotential dental office variation of distances between the 3-way T Portflow valve 110 and the gas input 306 of the gas flow controller 102,custom oxygen hoses will need to be made for each purchaser exercisingthis option. The valve 110 has first arm 114A and a second arm 114B thatextend longitudinally from each other, a body 116 that extendsperpendicularly from the center of the two arms 114A, 114B, and a handle118. The first arm 114A is coupled to the oxygen inlet port of aninhalation sedation system flow meter. The body 116 is coupled to anoxygen source.

The valve 110 has three different handle 118 positions, a firstposition, a second position, and a third position, and each handle 118position corresponds to a different mode that the system 100 can operatein. The first position is longitudinally along the first arm 114A, thesecond position is longitudinally along the second arm 114B, and thethird position is perpendicular to both the first and second arms 114A,114B.

The three different modes are:

1) Inhalation sedation for patient alone during non-mercury removalprocedures (handle position 1);

2) Oxygen breathing for patient, doctor and assistant during mercuryremoval procedures (handle position 2); and

3) Inhalation sedation for patient and oxygen to doctor and assistantduring mercury removal procedures (handle position 3). In this position,the control mechanism 318 for the patient is closed by turning itclock-wise until it is closed. Oxygen will be supplied via the gas flowcontroller 102 solely to the doctor and assistant stations with thisoption.

In use, the system 100 provides a breathing gas simultaneously to thedentist performing the filling removal, the patient receiving thefilling removal, and the dental assistant assisting in the fillingremoval. Because all individuals in the room receive a breathing gas viathis airtight breathing system 100, there is a significantly reducedrisk of inhaling any ambient mercury vapor. It should be noted that thesystem 100 only flows one way. Meaning, the breathing gas only flowsthrough the system 100 in one direction, from the gas source via theflow controller 102 to the nasal hood 222, and into the user's nose.When the user wishes to exhale, they simply do so through their mouth.Optionally, the user can exhale through their nose, and the exhaled gasleaves the nasal hood 222 via the one-way valve 810. The user does notexhale through their nose, and back into the system 100. It is notpossible due to the positive pressure flow of the breathing gas.

The first step of using the system 100 requires coupling the flowcontroller body 102 to a breathing gas source. Typically, the breathinggas source is an oxygen tank. Next, the patent, dentist, and dentalassistant each secure a breathing assembly 104 to their faces. Once allthree breathing assemblies 104 are secured to their respective user, theflow controller 102 is turned on via the on/off switch 304, and the flowof breathing gas to each breathing assembly 104 is adjusted via thecontrol mechanism 318 to an appropriate level. Once breathing gas isflowing to the three breathing assemblies 104, the removal of themercury filling can commence.

The present invention has the following advantages:

1) Currently, there is no comprehensive breathing gas system for useduring removal of mercury fillings. Current standard practice forremoval of mercury fillings involves using a standard nitrousoxide/oxygen facemask on the patient, and respirator masks on thedentist and dental assistant. The nitrous oxide masks are quite toobulky and may do not form an airtight seal with the patient, thereforeleaking in ambient air. Also, the dual supply tubes that are tightenedat the back of the dental chair disallow patient head rotation, which isa restrictive factor in removing mercury fillings. The respirator masksfor doctor and assistant may be effective in preventing the introductionof mercury vapor, but are claustrophobic, bulky, difficult to place,adjust and remove, and can interfere with dental magnifying glasses thatmost all dentists use. The present invention provides an airtightbreathing gas delivery system for the patient, dentist and dentalassistant, so that all three persons can breathe clean oxygen withoutfear of inhaling dangerous mercury vapors;

2) The nasal assembly of the present invention is low profile and doesnot block the patients mouth—providing ease of access to the mouth forthe dentist;

3) The nasal assembly and straps are made from soft, flexible materialsuch as silicone so that it is comfortable to wear during the fillingremoval;

4) Maximum comfort—less than 2 ounces in weight;

5) Ease of placement and removal with head strap attachments;

6) Effective nasal insert elements seal with users nares and prohibitintroduction of ambient air;

7) Clarity of communication between doctor and assistant compared to themuffled voicing inherent with respirator masks;

8) Effective disinfection, filtration and maintenance,

9) Removable in-line disposable filter element to assure no internalbacterial contamination of tube and bag assemblies;

10) Rotation of patient's head to better access operative sites comparedto the restricted lateral movements of nitrous oxide/oxygen nasal hoodswith dual tubes that cinch the patient's head to the dental chair;

11) Ease of breathing, as the breathing bag is less than 2 feet from thenasal assembly rather than at the remote flowmeter oxygen supply sourcecommon with N2O/O2 inhalation sedation systems; and

12) An emergency oxygen system for the patient.

Although the invention has been described in terms of a preferredembodiment, nevertheless, changes and modifications can be made which donot depart from the spirit, scope and teachings of the invention. Suchchanges and modifications are deemed to fall within the purview of thepresent invention as claimed.

What is claimed is:
 1. A breathing gas delivery system comprising: a) agas flow controller, the gas flow controller comprising a body having:i) an on/off switch coupled to the body for controlling breathing gasflow into the flow controller; ii) a body passageway disposed throughthe body; iii) at least one gas input disposed within the body, the gasinput comprising a gas input passageway disposed there through, the gasinput passageway being in fluid communication with the body passageway;iv) three gas outputs disposed within the body, each gas outputcomprising a gas output passageway disposed there through, each gasoutput passageway being in fluid communication with the body passagewayand the gas input passageway; and v) three control mechanisms disposedalong the body, where each control mechanism corresponds to and controlsone of the three gas outputs; b) three breathing apparatuses, eachbreathing apparatus comprising: i) a T-shaped gas input having two armscoupled to and extending perpendicularly to a body, the body having afree end; ii) a breathing bag coupled to the free end of the body of theT-shaped gas input; iii) a second length of tubing having two opposedends, wherein one end is coupled to a first of the two arms of theT-shaped gas input; iv) a filter containing at least one layer ofmaterial coupled to the other end of the second length of tubing; and v)a nasal assembly coupled to the filter; and c) three first lengths oftubing coupling the breathing apparatuses to the gas flow controller,each first length of tubing having two opposed ends, wherein one end iscoupled to a respective one of the breathing apparatuses and the otherend is coupled to a respective one of the gas outputs.
 2. The system ofclaim 1, wherein the control mechanisms each comprise a dial coupled toa needle valve that extends into the body passageway and controls flowof gas to the corresponding gas output.
 3. The system of claim 1,wherein the nasal assembly comprises a nasal hood.
 4. The system ofclaim 3, wherein the nasal hood comprises a one-way vent disposed in aside wall of the nasal hood.
 5. The system of claim 1, wherein the nasalassembly comprises a nasal hood and an airtight elbow coupling forcoupling the nasal hood to the filter.
 6. The system of claim 5, whereinthe elbow coupling comprises a sphere with two cylinders extending fromthe sphere.
 7. A method of using the system of claim 1, the methodcomprising the steps of: a) coupling the gas input to a gas source; b)securing a respective one of the breathing apparatuses to a face of eachuser; and c) turning on gas flow to the breathing apparatuses.
 8. Abreathing gas delivery system comprising: a) a gas flow controllercomprising a body having: i) an on/off switch; ii) at least one gasinput; and iii) three gas outputs; b) three breathing apparatuses,wherein each breathing apparatus comprises: i) a T-shaped gas inputhaving a body with two arms and a free end; ii) a breathing bag coupledto the free end of the body of the T-shaped gas input; iii) a secondlength of tubing having two opposed ends, wherein one end is coupled toa first of the two arms of the respective T-shaped gas input; iv) afilter coupled to the other end of the second length of tubing; and v) anasal assembly coupled to the filter; and c) three first lengths oftubing coupling the breathing apparatuses to the gas flow controller,each first length of tubing having two opposed ends, wherein one end iscoupled to a respective one of the breathing apparatuses and the otherend is coupled to a respective one of the gas outputs.
 9. The system ofclaim 8, wherein each nasal assembly comprises a nasal hood.
 10. Thesystem of claim 9, wherein each nasal hood comprises a one-way ventdisposed in a side wall of the nasal hood.
 11. The system of claim 8,wherein each nasal assembly comprises a nasal hood and an airtight elbowcoupling for coupling the nasal hood to the respective filter.
 12. Thesystem of claim 11, wherein the elbow coupling comprises a sphere withtwo cylinders extending from the sphere.
 13. A method of using thesystem of claim 8, the method comprising the steps of: a) coupling thegas input to a gas source; b) securing a respective one of the breathingapparatuses to a face of a user; and c) turning on gas flow to thebreathing apparatus.